Kim took to social media on Sunday to announce the death of her 55-year-old brother Christopher Cattrall.

'It is with great sadness that myself and my family announce the unexpected passing of our son and brother, Chris Cattrall. At this time we ask for privacy. We want to thank you all on social media for your outpouring of love and support in this trying time,' she posted to Twitter and Instagram along with a photo of her and Chris.

Sarah and SATC co-star Cynthia Nixon reached out to Kim on social media following the announcement.

'Dearest Kim, my love and condolences to you and yours and Godspeed to your beloved brother. Xx,' Sarah wrote in the comments section of Kim's heartbreaking announcement.

Cynthia also sent Kim her condolences, writing to her: 'Hey Kim such awful news. So sorry to hear. Sending you love. XO.'

Giving thanks: Kim publicly thanked her SATC co-stars, fans and friends on Tuesday for their support after announcing her brother's death on Sunday

Popular show: Sarah, Cynthia, Kristin Davis and Kim are shown in May 2010 in London promoting the film sequel Sex And The City 2